Hi guys, I run a store that specializes in a type of motorcycle that uses a plastic Acerbis tank and have the honor of owning other models with plastic tanks as well. After looking at the causes of deformation the only solution to the problem was to avoid gasoline with ethanol like the plague. Specially for storage or if you do not use your motorcycle often. The stuff is really harmful to the shape of plastic and wether it is because of the alcohol content in it or not, it really damages the tanks. I have a Ducati that was the cause of a lawsuit vs. Ducati and led to a recall and the free replacement of a tank. They replace it with a plastic tank by the way - Subsequent models incorporated a metal tank for the US market. By the way, the majority of countries out there do not use Ethanol, its predominant in the US. A Solution? : Metal tanks for the US market?